RHACHIPHYLLUM (AL. CALLIPTERIS) HEILONGJIANGENSIS (HUANG) COMB. ET EMEND. NOV. FROM THE WUCHIAPINGIAN WUTONGGOU FORMATION IN THE JUNGGAR BASIN, NORTHERN BOGDA MOUNTAINS, NORTHWESTERN CHINA

Callipterids are a group of late Palaeozoic pteridospermous plants, characterized by foliage formerly classified in the fossil-genus Callipteris Brongniart 1849 non Bory 1804. Callipterids originated in the Late Pennsylvanian, were widely distributed in the Cisuralian tropics. During the latest Cisuralian through Lopingian, they spread widely in Pangean tropics and northern temperate regions as significant elements in the Angaran floral province.

All four major flora provinces, Cathaysia, Angara, Euramerica and Gondwana, were represented in China during the Carboniferous and Permian. In total, 17 species of Callipteris were described from the Angaran province of China. However, many of them are based on very fragmentary and limited material; and the intraspecific variability of individual taxa was hardly considered. The assignment to Callipteris was not correct because the generic name Callipteris Brongniart 1849 is illegitimate as it is a later homonym of Callipteris Bory 1804, a genus of extant ferns. Recent reclassification divided callipterid foliage into five fossil-genera to accommodate different morphotypes formerly classified in Callipteris Brongniart, i.e. Rhachiphyllum Kerp 1988, Lodevia Haubold et Kerp 1988, Arnhardtia Haubold et Kerp 1988, Gracilopteris Kerp, Naugolnykh et Haubold 1991 and Dichophyllum Elias ex Kerp et Haubold 1988.

We report new a material of Rhachiphyllum (al. Callipteris) heilongjiangensis (Huang) comb. et emend. nov. from the Dalongkou section, Xinjiang Uygur Autonomous Region, northwestern China. A number previously introduced species appear to be conspecific are and placed in the synonymy of R. heilongjiangensis. The species is characterized by particular frond architecture, typical elongate pinnules with a clear midvein and densely spaced lateral veins that depart at a low angle. The occurrence of herbivory within R. heilongjiangensis suggests the selective feeding of herbivores and a wide range of foliar herbivory on late Palaeozoic peltasperms. Sedimentologic, geochemical and palaeobotanical evidence indicates that R. heilongjiangensis grew around a lake in a humid climate.